render passes vs layer attributes

# 1 24-10-2012 , 12:03 PM

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Can anyone tell me the real differences between render layer attributes and associated passes? for example, getting a depth map or AO render seems possible using both methods.. but what's the real difference between the two?
I realise it's all dependent on 'what you want' - I just want a simple way of getting a depth map. I can get a luminance layer set up, but it seems it'd be much easier to add a pass to the layer. Passes sound like the answer, though I can never get them to work. On top of these there's contribution maps, overides. And a Z depth checkbox in the renderable camera settings.... that doesn't seem to do anything either.

Every tutorial seems to go about things a different way, so it's difficult to know which advice to take to avoid making things more complicated than need be.

thanks

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# 2 24-10-2012 , 01:41 PM

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The thing with depth map passes is they take really ages to render so a great cheat that works super fast with a really easy set up to get a depth pass is to give everthing in the scene a surface shader with the color set to white,then add Environment fog in render globals and set the fog color to Black with color based transparency set to off.You can set the distance for solid black (end of your scene) then in the clipping plane tab set Fog near distance to 0000 (the camera).
The render will take seconds as opposed to minutes or hours and give really nice depth of field.

In answer to your original quest about the difference of the two ,Render Layers you have a new layer for each pass so each layer renders separately and therefore takes longer than Render passes which in effect renders all passes in a single render.

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Last edited by jsprogg; 24-10-2012 at 01:58 PM.

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# 3 24-10-2012 , 01:49 PM

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Really? I haven't noticed depth maps taking very long, but maybe the scenes I tried weren't hugely complex.

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# 4 24-10-2012 , 02:01 PM

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no mine don't seem to take very long. It's just getting a simple approach that can be added to a layer so I can batch render a layered PSD.
thought it would be a simple affair to put all the geometry on a layer, add a camera depth pass and render... but it seems I'm missing something...?

the fog idea sounds good though, but would it work in a layered render - ie. wouldn't the fog go across the entire render if it's a global setting.

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# 5 24-10-2012 , 02:01 PM

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Stwert for a single image it might not make a difference to you, but the render time could be 2 minutes as opposed to 15 seconds which in an animation is a huge saving per frame.You don't need lights in the scene or any final gather it's a really fast render

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Last edited by jsprogg; 24-10-2012 at 02:17 PM.

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# 6 24-10-2012 , 02:06 PM

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wouldn't the fog go across the entire render if it's a global setting.

Originally Posted by se7enhedd

no in the layer you can set the fog as a layer overide so it is only for that layer

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# 7 24-10-2012 , 10:22 PM

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no in the layer you can set the fog as a layer overide so it is only for that layer

Originally Posted by jsprogg

sounds very interesting, but a much of a work-around as anything. surely someone must be able to shed some light on these mysterious passes...

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# 8 24-10-2012 , 10:44 PM

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Depth doesn't take much longer for me either. Are you rendering the depth float? You could use depth remapped at 16bit.

Also, a faster way than the fog would be to just project a black and white ramp from the render camera over all the objects.

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# 9 24-10-2012 , 11:14 PM

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There's a few free lessons at the start of this course that should shed some light: https://www.digitaltutors.com/11/trai...575&autoplay=1
(apologies to simplymaya).

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# 10 29-10-2012 , 02:52 AM

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To sum up the passes this is I've to say.

Render Passes takes no additional time to calculate passes. (If You're breaking down your scene file to composite. Which means only the material properties used to build up the scene)

Render Layers takes additional time but has the feature to Override attributes. ( Allows to override attributes per layer. This is useful when you would like to turn off expensive indirect illumination for the passes.)

Contribution map is used to separate object from the scene, and individually different passes can be assigned to each Contribution map.

Last edited by zestken; 29-10-2012 at 03:01 AM.

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# 11 06-11-2012 , 03:01 PM

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I'm obviously missing something with these passes as every time I try to use them I end up with a blank layer... I'll have to set aside a weekend (somehow!) to tackle them with the DT.

@zestken - thanks for the summary - tho I'm afraid I'm not attuned enough to 3D methodology for it to really make much sense! ={

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# 12 07-11-2012 , 03:23 AM

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I'm obviously missing something with these passes as every time I try to use them I end up with a blank layer... I'll have to set aside a weekend (somehow!) to tackle them with the DT.

@zestken - thanks for the summary - tho I'm afraid I'm not attuned enough to 3D methodology for it to really make much sense! ={

Originally Posted by se7enhedd

Yup, that should help you a lot. Don't just skip them thinking you could do it afterwards but put into practice after each lesson.